The invention relates to a remote monitoring system for remotely monitoring a single- or multi-function installation of moderate size by telephone, e.g. for use in a home or a shop and other premises that may be attached thereto, or for use in a workshop or a small establishment.
Since progress in telephone networks now makes it possible to transmit both speech signals and data signals easily, users are looking for ways of taking advantage of the possibilities of interconnecting telephone terminals connected to the same network for the purpose of remotely monitoring the operations of installations by telephone without geographic constraints.
"Remote monitoring", sometimes also called "remote action", should be considered herein as covering a wide range of applications requiring one-way or two-way transmission, usually of short messages that are generally produced on a sporadic basis.
This range of applications includes, in particular, remote control, remote operation, and remote surveillance.
An apparatus in an installation as mentioned above may be remotely controlled over the switched telephone network by means of a specialized transmitter which is connected to the telephone network either via a conventional telephone set or directly as a telephone set. The transmitter is suitable for generating special remote control signalling which is normally different from the signalling used for operating the telephone network. The special signalling is received by a specialized receiver whose function is to control the apparatus accordingly, and for this purpose the receiver is connected to the telephone network in comparable manner to the transmitter. Naturally, in order to be able to transmit special remote control signalling, a telephone connection must be set up between the specialized transmitter and receiver over the telephone network using the procedure appropriate for the network. Facilities for two-way transmission are often provided.
Remote control systems of this type are generally expensive, in particular because they use special equipment which is often associated with a single specific function.